Apple powdery mildew: literature and research overview

Abstract

Apple powdery mildew, caused by the fungus Podosphaera leucotricha (Ell. and Everh.) Salm., is a disease found in apple growing regions world-wide, and is economically important in many of them. Most of the research on this pathogen pertains to various methods of control, particularly with fungicides and host resistance. Fungicide effectiveness and development of new fungicides have been most prominent. A considerable amount of research has been done in epidemiology. Host resistance genetics and mechanisms, components, and development of resistant cultivars have also been emphasized. Aspects of research on apple powdery mildew that have not been explored in as much depth are also reviewed. Some of these areas include the role of cleistothecia and ascospores in life and disease cycles, heterothallism versus homothallism, and growth of the fungus on artificial media. Additional research needs from each aspect are proposed. This report is based on a comprehensive review of the current literature on apple powdery mildew.